There is strong interest in methods for the preparation of selectively fluorinated organic compounds, due in part to the profound influence that fluorine incorporation can have on the physical and chemical properties and biological activity of molecules.
Hypervalent sulfur fluorides possess an octahedral geometry unlike carbon-based fluoroorganic systems, which allows the design of linear trans-tetrafluorosulfanyl bridged structures which are of particular interest for highly fluorinated materials, such as liquid crystal for active matrix LCDs (Kirsch, P., et al., Bis(4-nitrophenyl)tetrafluorosulfuranes: Synthesis, Isomerization and Structural Characterization. Journal of the American Chemical Society, 1999. 121(49): p. 11277-11280).
While hypervalent sulfur fluorides, e.g., tetrafluorosulfanyl (SF4) compounds, are known to be useful in various applications, such as in electro-optical display devices, these compounds have traditionally been prepared by direct fluorination, which has several significant limitations. For example, the substrates suitable for the oxidative fluorination step must themselves be unreactive toward fluorination. In other words, the substrates are generally limited to electron withdrawing group-substituted diaryl sulfides or trifluoromethylthioarenes. This requirement inherently restricts the nature and type of substitution that can be employed with the SF4 group.
Thus, a need exists for improved methods of preparing tetrafluorosulfanyl compounds that are not limited by the requirement for direct fluorination, and for tetrafluorosulfanyl compounds that can accommodate a broader variety and nature of substitution.
While certain aspects of conventional technologies have been discussed to facilitate disclosure of the invention, Applicants in no way disclaim these technical aspects, and it is contemplated that the claimed invention may encompass one or more of the conventional technical aspects discussed herein.
In this specification, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was, at the priority date, publicly available, known to the public, part of common general knowledge, or otherwise constitutes prior art under the applicable statutory provisions; or is known to be relevant to an attempt to solve any problem with which this specification is concerned.